Commander Pete Ericsson and Technician Cosmo Georgiadis have just departed on Expedition 47 and now I've been informed that the Japanese launch has been delayed for a couple of days, due to the weather, so it looks like I'll be up here alone for a while. That's a new experience. Don't usually get so much privacy around here. Now I've got days of it instead of hours.

In ten days' time, the three-man Russian crew arrive, bringing our number back up to six. Three months at full capacity is going to be hard work, but it will be good to see my old friend Ilya again.

It's weird up here with no-one around. Arth (R3 or Robonaut 3 to strangers) tries to keep me company but as good as artificial intelligence has got, he's just not the same as having other humans around. Found myself playing music most of the time today while going about my routine tasks. There's a lot to do when all the chores fall to me.

Arth's ability to play some simple games is a mixed blessing. He's keen but far too good at all the games he knows. Maybe I should teach him some new ones? That could be a challenge.

I'm tired. Just a quick entry before I grab some sleep. Both up-link and down-link failed in the early hours. Spent all day scanning tech manuals, running diagnostics and changing boards. The up-link heartbeat came back about an hour ago, but the downlink is still dead. No communication with Mission Control since yesterday. I would feel better with some other faces around here to help sort out the problem.

Something's wrong. No sign of the Japanese crew and still no communication with Mission Control. Roscosmos is dead too. Been monitoring the ham radio system, but it hasn't received anything for hours. I entered the Russian module today and cranked up their down-link, but it's also dead. My Russian skills struggle with their manuals but it all seems to check out. It seems there's just nothing out there to receive. That can't be.

Getting seriously worried now. Still no sign of the Japanese crew and no contact with MC. Arth did an EVA to check out the radio antennas. Everything was fine. The up-link heartbeat has stopped so now the entire comms system is dead. I opened the shields on the cupola and sat there watching for a while – view is always spectacular. Saw something that made me freak out. No lights! The nightside of Earth has no lights! Not one. For a while, I thought I saw a few but checking with the telescope showed there were just bush fires or forest fires. How can the whole planet have a blackout?

I've got the radio system scanning for any broadcasts at all. It's got to pick up something. I switched off Arth and stowed him. Without tasks to do all he wants to do is play games.

What the hell is going on down there?

Had a funny turn yesterday. Still no contact and I assumed the worst. If some catastrophe has wiped out the people down below, then I'm trapped alone in a tin can sailing along at 5 miles per second. Too much to take in one go, but calmed down a bit now. A population of 7 billion doesn't just get wiped out in one day. Even a nuclear war would have survivors.

Obviously, something bad has happened, and they need time to deal with it. I just need to sit it out. Expedition 46 brought enough supplies to keep six of us going for three months. With just me, that gives me eighteen months. With care, I should be able to make that last two years or more. Better still the hydroponic farm experiment is up and running. MC expected four to five crops per year. That's going to extend my food supply even further and help the oxygen situation.

The only thing I can't ration is fuel for the boosters. Regular burns are necessary to keep this crate in orbit.

Just need to stay calm, keep everything ticking over nicely and sit it out. Comms will probably be re-established in the next few days. Then all will return to normal and I can find out what's going on.

Boredom and stress are killing me. Playing music all the time is helping a little. Apart from eating and my exercise sessions, spent the day inventorying all the supplies and spares on the station. As long as we don't have too many electronic failures, should be good for at least six months. Don't foresee it being too hard to get by for at least a year.

First bit of good news! Found a stash of extra food sachets in the Russian module. I won't just steal them – could be very embarrassing if the Russian crew turns up as scheduled – but it's good to know they are there.

Still alone and really feeling it now. Sometimes I play music, but most of the time I seem to prefer listening to the sounds of the station itself. The constant hums and whines of pumps, filters, heaters and cooling systems is oddly comforting. Wondering about unpacking Arth.

Re-ran all the diagnostics on the comms system. Still no trace of any fault and nothing being received. Apart from sporadic wildfires on the surface, still no lights down below. Saw some impressive electrical storms though.

Decided to work through my options. I can sit it out here and eventually starve or suffocate, or jump in the Soyuz and head home to whatever's waiting there. Without a recovery team on the ground, I don't know what my chances would be, probably low. Kazakhstan isn't the best place to find yourself without transport. There's always a third option, but I won't even consider that.

I'm sure the best plan is to just sit it out, for a few weeks at least.

Unpacked Arth. He seemed genuinely pleased to see me, but I know that's just my imagination. No time passes for him when he's powered down but I guess he knows just how long he's been packed in his locker. Not sure whether this personality thing JSC added since R2 is a good thing, but it makes him more interesting.

He helped me perform some routine maintenance on the water recyc system. Got to keep that one in good working order. We played poker this evening. Arth is so slow with the cards and I didn't like to tell him that I could see his cards reflected in his shiny face. That gold visor might look cool but it's a massive disadvantage for him in card games.

Still nothing from Earth. It's like the whole place is deserted. Tried not to think about my family too much. Trained Arth to prepare food sachets today. He doesn't understand flavours at all. Had beetroot and cheese sauce for lunch. I won't have to prepare all my own meals, but I will need to tell him which sachets to use.

The hydroponic farm is doing well. With no parasites and no watering to do, it pretty much looks after itself. I just need to check everything is working and do a little pruning now and again. The composter smells disgusting – hope that's not going to be a problem.

Saw huge bush fires around Southern Australia today. Still wondering what happened down there. Best guess is some sort of disease outbreak but what could take hold and incapacitate so many countries so fast?

Toyed with the idea of growing a beard. Asked Arth's opinion but he doesn't seem to understand the concept. Beard, hat, shades, it's all the same to him – just something you wear on your face. Still holding out some hope that there will be some contact soon, but I'm probably kidding myself.